Inheritance: HqlStatement
		public void AddHavingClause(HqlBooleanExpression where)
		{
			if (_hqlHaving == null)
			{
				_hqlHaving = TreeBuilder.Having(where);
			}
			else
			{
				var currentClause = (HqlBooleanExpression) _hqlHaving.Children.Single();

				_hqlHaving.ClearChildren();
				_hqlHaving.AddChild(TreeBuilder.BooleanAnd(currentClause, where));
			}
		}
		private void ExecuteAddHavingClause(HqlHaving hqlHaving)
		{
			if (hqlHaving == null)
				return;

			if (!_root.NodesPreOrder.OfType<HqlHaving>().Any())
				_root.AddChild(hqlHaving);
		}